Idle Problem

[Oke]

Hy guys.
I have a problem with my mx3. I have changed the air filter with a BMC Twin Air, and made some adaptions, but all the hoses are put back, and removed the catalizator. I changed the fuel filter, but i think this can't be a problem. When i started the car the idle was normal, but after a few drives the car idle is siting at 2000rpm, and some time's it's at 1500rpm. What can pe the problem, do y need to reset the ECU, how i can do that? I dont know what to do, and i can fiind in the region a tester for this car.
Please help, and sorry for the bad english, i am learning.
I will put some pictures with the modification.

[kulluminati777]

your pictures dont work. Maybe you didnt plug the MAF back in. I do that all the time. Also to reset the ECU just disconnect the negative battery cable get inside and hold the brake pedal down for at least a minute. Then hook the battery cable back up and turn the car on and let it idle for a few minutes so the ECU can learn your new stuff you put on.

[Oke]

I have put the MAF back. I tried today to ajust the idle from that screw on top but i only go to 1200rpm and the screw is full closed. Can the catalyts be the problem because i removed? I tried to take out the negative wire, and whait 15min press the brake pedal a few times, and then start the engine but nothing hase changed, maybe i have to do what you told me. I will try to put again the pictures.


Thx for the help, until now.

[atx_mx3]

Take the filter off and start the car. If the filter is contacting the end of the VAF, it will raise the idle.

[kulluminati777]

Uh i was always told the VAF has to sit horizontally but i could be wrong. Also what made you want to go with that intake? it seems worst then the stock set up? Your only supposed to adjust the idle screw with the TEN and GND jumped with a wire or a paper clip (so the car is in diagnostic mode)

hey and nice strut bar

but if all you did was put that intake on and nows its acting funny i would suggest getting a different set up or go back to stock

[atx_mx3]

Uh i was always told the VAF has to sit horizontally but i could be wrong.

I have also heard the same thing. I think there is some truth to this, but for the most part, my VAF has never been perfectly level. Its always had a downward slant to it and my car idles perfect.


Pull the filter off, start it and see it it changes.

[Oke]

U Your only supposed to adjust the idle screw with the TEN and GND jumped with a wire or a paper clip (so the car is in diagnostic mode)

Can you explain this procedure a litle, because i am new with this type of cars. The strut bar is mazdaspeed i bought the car with it, i dont know if that was there from new or is tuned after .
I was thinking about the catalyst, maybe that can be, someone got this problem after the change?
I will remove the filter to se what hapens, and try again to reset the ECU and maybe raise a litle the MAF.
If somebody know's something else please let me know.

Thanx again for the help until now.

[davmac]

I assume your idle is steady (not surging) but just too high. If true then:
1. Check the cable connected to your throttle. Make sure there is a little slack in the cable when your foot is off the gas (at idle). If it is too tight it will hold the throttle open and cause the idle to be high.

2. Pull the intake tube off and make sure the throttle opens and closes completely. There might be some carbon build up holding the throttle plate open.

The catalytic converter has nothing to do with the idle.
The position of the VAF might have some impact - it works best when nearly horizontal. But, when the VAF is more vertical the issue is it does not open under idle because gravity holds it closed. The problem would be too low idle - or the car might not idle at all.

[Oke]

Hy, thanks for the answer.
1. The cable has a little slack, i tried that.
2. The throttle body is ok, i cleaned, before mounting.

The car was ok, after the instal, only after a few hard drives, it started to idle spot on at 2000rpm, and some times 1500-1600rpm, and after i played with the screw it go down at 1200-1300rpm, but it is fully closed.
I will try to reset the ecu with the full brake pedal method (i tried already 15min of no power and a few brake pedals but nothing changed) And i will se if i lift the MAF or maybe remove the air filter as told to see what hapens.
But i am woried because the car just after the modifications was normal, and now is doing this things, please help if some one knows something, thank you.
In the weekend i will try the method told to me, maybe thei will work, but i dont know what to say, i hope only.

Thanks for the help and i am waiting for advices. Sorry for the bad english.
To give back to the comunity fell free to ask me every thing about body work and polishing.

[mx3_ryder]

Did it do it before you cleaned the throttle body? The reason you thought it was fine after the install was probably because it wasn't fully warmed up yet? Did you do what atx_mx3 said and take off the filter while running to see if it changes. You should have left the idle screw alone because that wasn't your problem. Now you have two problems. The original problem and incorrect idle adjustment.

[davmac]

Either the engine thinks it needs to fast idle (like when the engine is cold) or you need to take care of some tune up setting.

You might start by confirming some settings:
- set throttle position sensor TPS see manuals F2-152 and a few pages
- set timing and idle see manuals F2-73 and a few pages after

If the engine thinks it needs to idle fast (like when the engine is cold) then check:
- coolant temp sensor
- Idle Air Controller (IAC) on the bottom of the throttle body

Note that both the items above will not work correctly if you are low on coolant and there is air in the coolant. So check your coolant level and purge any air from the system.

[Daninski]

I agree, start by checking your coolant level when the engine is cold. You may need to burp the system as there could be air trapped effecting the IAC. I find rapidly squeezing the rad hose helps remove air from the system, do this with the coolant cap on then recheck your coolant level.
When you adjust your idle, TPS or timing you have to jump TEN and Gnd in the diagnostics box first. You also need to use a separate rpm gauge not the tach on your dash to set your idle.

TPS Adjust
Connect ohmeter to 2 bottom pins (BR and BK/DB) and you should get continuity. If not, loosen 2 TPS retaining bolts and rotate until continuity has just barely been achieved. Semi tighten 2 TPS bolts.
Insert .006" (0.15mm) feeler gauge between the throttle stop screw and throttle lever. This should not break the continuity. If it does break continuity, slightly adjust TPS rotation again to regain the continuity. Insert the gauge in and out a few times to verify.
After confirming continuity with 0.15mm feeler gauge, insert a .020" (.50mm) feeler gauge. This should just barely break continuity. If not re-adjust TPS rotation again. Re-confirm by re-inserting feeler gauge.
In essence, continuity on initial connection to TPS.
Continuity with .15mm gauge inserted.
No continuity with .50mm gauge inserted.
Tighten down TPS retaining bolts.
Re-connect TPS connector.

Once you've adjusted the idle and or TPS let the car run for at least 15 minutes so the ECU can learn the new settings.

Idle Setting
Before adjusting remove the screw and ensure its clean and not damaged.
The screw on the top of the throttle body is what your looking for. Start by adjusting it about 3 turns out then start the engine. With the engine warmed up turn it in till the engine starts to die then gradually turn the screw out untill you read 650 RPM in Diag mode (Ten and Grd jumped). If you turn it too far out your engine will be less responsive so if it feels sluggish afterwards readjust the screw.

[Oke]

Hy guys, sorry for the absents, but i had a lot of work, and i don't remember the pasword of the id to conect from my mobile .
I want to thank every one for the help. I checkt the level of coolant, it's almowst full, i tried with TEN and GND with a led to see if something show, but nothing, and the car did not to anithinkg. Daninski thx for the help, but i dont understand with TPS adjust how it works . I am thinking of puting the old kit back.
Or maybe get a made one allready but here in Romania i can't fiind something, maybe you know some exactly materials i need for it, to make it my self, because i will like to try to make it my self not at the shop. I tried to reset the ECU with 15m of no batery and a few brake pedals, but nothing changed. I can see if i pus with my hand the throtel position back the rev goes a litle down, but after i acceleret it remains up.
I don't know what to do, and my fuel consumption is 14L/100km and it's not that responsive any more.
Daninski can you explain more simple what to do, or maybe you other experienced guys, thank you.
I will post a picture with the car that i like

Thank you again and sorry for the bad english.

[davmac]

Fuel consumption and responsiveness are all related to idle adjustment.

You have the air filter cone jammed on to the airflow sensor (VAF - the black thing just behind the air filter cone). The air filter cone might be holding the VAF open. This would explain all the problems you are having.

First pull off the air filter cone and drive around a bit to see if there is any change. You will not hurt anything if you are without an air filter for only a short time.

If that does not help then you need to do some tuning. Daninski has given you directions to set the Throttle Position Sensor (TPS). It is the small black thing on the throttle body on the other side from where the throttle cable is attached. There are 2 small bolts that hold it in place. You will loosen the bolts and turn it while you have a feeler gauge between the throttle cam (where the cable is connected) and the stop on the throttle body. You will turn the TPS (the black thing) until you get proper measurements on your ohm meter. Basically you are setting the position of the TPS so it can tell the engine computer that the throttle is closed.

You will have to use a multimeter (ohm or resistance setting) and feeler gauge to set the position correctly for closed throttle. Here is the link to the page in the service manual. The directions for setting the TPS start at the bottom and are covered more on the next page. I hope the pictures and directions help. Setting the TPS position is delicate. You need to check and re-check until you are sure it is right. Set the TPS first and then set idle speed and timing.

[Oke]

I will try to remove the air filter to see what happens, and if not i will go to a mechanic-electrician with the expleain from here to show him wat to do, because i dont want to mess anithing there. If i screw some parts i can't fiind any to buy, or is very expensive.
Last night at the races i loss every one, every single one, by a car lenght it was so anoing, (oponents BMW 320, Mitsh Lancer 1.8 moded, Passat VR6), i think this problem is responsabil for this.
I have encountered a noder problem, i tried to greas the sunroof, and after that i sow in the back of the driver seat a lot of whater, is the greas the problem, where i can fiind the drain sistem to make it clear? Sory for this question but i dont know where to post it.
I removed the air filter, but nothig hapend, and i tried to push with the hand the VAF inside, and the idle went down but when is full open the idle is again at 1500-1800rpm. When i change the gear in high revs the exhaust explods a litle, and in idle is not going smoth (brrrrmm brr BRRm brrrmmm BRRm brrrm brmmmm) The idle screw is opend 2 and half complete ratation from the closed position. With the stock air filter and stuf the car i think is going beter. The car is not puling hard after 4000rpm when i got it at this rpm's the car was puling good. Can the catalizator be the cause as well. The sparks-plugs and the wires are ok, everthing seems to be ok, but it's not puling. I don't know what to do and i cant fiind a mechanic in the area, so please help.
Another thing, i don't have to cables puling the accelartion, only the cable that is down in the picture, why?
Thank you again, everyone
(i edit this post 3 times, sorry for the bad english)